Heretofore, as packaging materials for foods, such as retort foods, pharmaceuticals, or industrial chemicals, a laminate packaging material which contains a metallic foil excellent in barrier properties of oxygen or moisture and in which the metallic foil is laminated between a substrate film and a sealant layer in order to prevent the chemical change, degradation, decomposition, and the like of contents has been widely used (Patent Document 1).
On the other hand, in recent years, in connection with a reduction in the size and the weight of various electronic devices, such as OA devices (e.g., personal computers), cellular phones, game machines, headphone stereos, and electronic notebooks, a lithium ion polymer secondary batteries has been increasingly used from the viewpoint of achieving a reduction in the size and the weight also as a battery of a power source portion in many cases. In the lithium ion polymer secondary battery, when an electrolytic solution in the battery reacts with water and then hydrofluoric acid is generated, a reduction in the performance of the battery is caused or liquid leakage occurs by corrosion of the case. Therefore, the same laminate packaging material as above having excellent water vapor barrier properties and high sealing properties has been increasingly used as a material for use in the case (storing case).
More specifically, as the case material of the lithium ion polymer secondary battery (packaging material), a laminate packaging material in which an outer layer containing a heat-resistant resin film of a polyester type, an epoxy type, an acrylic type, or the like, an intermediate layer mainly containing an aluminum foil as a water vapor barrier layer, and an inside sealant layer containing a heat adhesive polyolefin resin for sealing a polymer electrolyte which is the content are laminated in order and integrated has been used (Patent Documents 2 and 3).
The laminate packaging material for battery case described above is molded into a three-dimensional rectangular parallelepiped shape or the like by bulging or deep draw forming in order to increase the capacity as much as possible to charge a polymer electrolyte, and then used as a battery case in many cases.